This invention relates to a metering valve for dispensing pressurized liquids, particularly for use with containers of the so-called spray-can type.
Currently available on the market are metering valves for spray-cans, which are so constructed as to allow a pre-proportioned amount of the product to be dispensed at each actuation of the valve control pushbutton.
Such valves, in one known form thereof, comprise essentially a bowl element which is associated in sealed relationship with the mouth of the container or can be means of a folded seam collar. Within said bowl element, there is axially slidable, against the bias of an elastic means, a valve stem.
Inside the bowl element, there is further provided a cylindrical portion, generally formed from an elastically deformable material, which defines along the bottom portion thereof a lip type of seal adapted for engagement with the valve stem, in contact relationship therewith, when said stem is in its dispensing position. More specifically, the stem can be actuated to selectively put the metering chamber defined between said stem and the cylindrical body, into alternative communication with the outside, and hence in a dispensing condition, or with the inside of the container or can.
With the latter approach, it happens that, where the useful volume of the metering chamber is to be changed, i.e., when it is desired to change the amount of product dispensed at each actuation, the cylindrical body must be replaced as a whole, along with the bowl element and the collar which secures it to the container.
It will be appreciated, therefore, how in order to change the dispensed proportions the majority of the metering valve components have to be replaced with others having different dimensions; thus to accommodate the wide range of proportions required, the manufacturer is obliged to store high quantities of different size components, which creates a problem both as regards the inventory and the production thereof.